Surgical instrument including an adapter assembly and an articulating surgical loading unit

ABSTRACT

An adapter assembly includes an articulation nut, an articulation link, and a drive belt operably coupled to a distal portion of the articulation link. The articulation link has a proximal end portion operably coupled to the articulation nut, such that rotation of the articulation nut results in translation of the articulation link. The drive belt has a distal end portion configured to be operably coupled to a proximal end portion of a surgical loading unit, such that movement of the drive belt articulates the surgical loading unit relative to the adapter assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/829,801 filed Apr. 5, 2019, the entire disclosure of which is incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates generally to surgical instruments for endoscopic use and, more specifically, to surgical instruments including adapter assemblies that articulate an attached surgical loading unit.

Background of Related Art

Various types of surgical instruments used to endoscopically treat tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, anastomoses, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical stapling instrument. Typically, surgical stapling instruments include an end effector having an anvil assembly and a cartridge assembly for supporting an array of surgical staples, an approximation mechanism for approximating the cartridge and anvil assemblies, and a firing mechanism for ejecting the surgical staples from the cartridge assembly.

During laparoscopic or endoscopic surgical procedures, access to a surgical site is achieved through a small incision or through a narrow cannula inserted through a small entrance wound in a patient. Because of limited area available to access the surgical site, many endoscopic surgical instruments include mechanisms for articulating the end effector of the instrument in relation to a body portion of the instrument to improve access to tissue to be treated. In addition, some end effectors have a knife shaft that translates therethrough to tissue grasped by jaws of the end effector. During articulation of the end effector, the knife shaft experiences a bending moment and/or a shear force that may degrade the knife shaft over continued articulation of the end effector.

Accordingly, it would be beneficial to provide an improved surgical instrument, which includes an improved mechanism for articulating the end effector relative to the body portion and without damaging a knife shaft that moves through the end effector.

SUMMARY

In an aspect of the present disclosure, an adapter assembly is provided and includes an articulation nut, an articulation link, and a drive belt operably coupled to a distal end portion of the articulation link. The articulation link has a proximal end portion operably coupled to the articulation nut, such that rotation of the articulation nut results in translation of the articulation link. The drive belt has a distal end portion configured to be operably coupled to a proximal end portion of a surgical loading unit, such that movement of the drive belt articulates the surgical loading unit relative to the adapter assembly.

In aspects, the adapter assembly may further include a pulley operably coupled to a proximal end portion of the drive belt. The drive belt may be wrapped about the pulley.

In some aspects, the adapter assembly may further include a proximal housing having the pulley rotationally supported therein, a distal housing having a distal end portion configured to be pivotably coupled to the proximal end portion of the surgical loading unit, and a tension screw disposed between the proximal and distal housings. The tension screw may be configured to adjust a distance from which the proximal housing is spaced from the distal housing and, in turn, adjust a tension in the belt drive.

In further aspects, the distal end portion of the articulation link may be operably coupled to a linear section of the drive belt.

In other aspects, the distal end portion of the articulation link may have teeth, and the drive belt may have teeth on an inner surface thereof interfacing with the teeth of the articulation link.

In aspects, the articulation link may include a fin extending from the distal end portion thereof. The teeth of the articulation link may be disposed on an outwardly-facing surface of the fin.

In some aspects, the fin of the articulation link may be enclosed by the drive belt.

In further aspects, the proximal end portion of the articulation link may be received in the articulation nut.

In other aspects, the proximal end portion of the articulation link may have a threaded outer surface interfacing with a threaded inner surface of the articulation nut.

In aspects, the adapter assembly may further include an articulation input shaft. The articulation nut may have teeth on an outer surface thereof interfacing with teeth on the articulation input shaft.

In some aspects, the adapter assembly may further include an outer housing having the articulation nut rotationally supported therein, and an outer tube extending distally from the outer housing. The outer tube may have the articulation link axially supported therein.

In further aspects, the adapter assembly may further include a rotation gear disposed about the articulation nut and within the outer housing. The rotation gear may be non-rotationally fixed to the outer tube, such that the outer tube is configured to rotate about a longitudinal axis thereof in response to a rotation of the rotation gear.

In another aspect of the present disclosure, a surgical instrument is provided and includes the adapter assembly and a surgical loading unit. The loading unit has a first pulley non-rotationally fixed in a proximal end portion thereof. The drive belt of the adapter assembly has a distal end portion operably coupled to the first pulley, such that movement of the drive belt rotates the first pulley to articulate the surgical loading unit relative to the adapter assembly.

In aspects, the adapter assembly may further include a second pulley operably coupled to a proximal end portion of the drive belt. The drive belt may be wrapped about the first and second pulleys.

In some aspects, the adapter assembly may further include a proximal housing having the second pulley rotationally supported therein, a distal housing having the first pulley rotationally supported therein, and a tension screw disposed between the proximal and distal housings and configured to adjust a distance from which the proximal housing is spaced from the distal housing and, in turn, adjust a tension in the belt drive.

In further aspects, the proximal end portion of the articulation link may be received in the articulation nut and may have a threaded outer surface interfacing with a threaded inner surface of the articulation nut.

In other aspects, the surgical loading unit may include an anvil, a staple cartridge assembly pivotably coupled to the anvil, a lead screw disposed within the staple cartridge assembly, and a knife operably coupled to the lead screw. The knife may be configured to move through the staple cartridge assembly to pivot the staple cartridge assembly toward the anvil in response to a rotation of the lead screw.

In aspects, the adapter assembly may further include a rotatable drive shaft having a distal end portion coupled to a proximal end portion of the lead screw via a universal joint.

BRIEF DESCRIPTION OF THE DRAWINGS

Surgical instruments including embodiments of the presently disclosed adapter assemblies and surgical loading units are disclosed herein with reference to the drawings, wherein:

FIG. 1A is a perspective view of a surgical instrument including an adapter assembly and a surgical loading unit, with a staple cartridge body of the surgical loading unit shown removed from a chassis of the surgical loading unit;

FIG. 1B is a perspective view of the surgical instrument of FIG. 1A, with the staple cartridge body of the surgical loading unit shown installed in the chassis;

FIG. 2 is an exploded view of a proximal end portion of the adapter assembly of FIG. 1A;

FIG. 3 is a side, cross-sectional view of the proximal end portion of the adapter assembly;

FIG. 4 is an exploded view of an articulation assembly of the adapter assembly and the surgical loading unit;

FIG. 5 is a side, cross-sectional view of a distal end portion of the adapter assembly and the surgical loading unit;

FIG. 6 is a top view of the distal end portion of the adapter assembly, with an outer tube of the adapter assembly removed, and the surgical loading unit;

FIG. 7A is a perspective view of an alternate embodiment of a drive belt of the articulation assembly;

FIG. 7B is a perspective view of yet another embodiment of a drive belt of the articulation assembly;

FIG. 8 is a side, perspective view of a surgical loading unit being articulated relative to an adapter assembly by another embodiment of an articulation assembly;

FIG. 9 is an exploded view of the articulation assembly and surgical loading unit of FIG. 8;

FIG. 10 is a side, perspective view of the adapter assembly of FIG. 8, illustrating a side, cross-section of the surgical loading unit of FIG. 8; and

FIG. 11 is a top, cross-sectional view of the articulation assembly of FIG. 8 shown articulating the surgical loading unit relative to the adapter assembly.

DETAILED DESCRIPTION

Persons skilled in the art will understand that the adapter assemblies and surgical loading units specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims.

As used herein, the term “distal” refers to that portion of the surgical instrument which is farthest from a clinician, while the term “proximal” refers to that portion of the surgical instrument which is closest to the clinician. In addition, as used herein, the term clinician refers to medical staff including doctors, nurses and support personnel.

The present disclosure is directed to a surgical instrument including an adapter assembly configured to be actuated by a hand-held actuator or a surgical robotic system, and an articulating surgical loading unit coupled to the adapter assembly. The adapter assembly includes an articulation mechanism that drives an articulation of the surgical loading unit relative to the adapter assembly. The articulation mechanism includes an articulation nut, an articulation link that translates in response to a rotation of the articulation nut, and a belt-driven pulley system that operably couples the articulation link to the surgical loading unit. The translation of the articulation link causes a belt of the belt-driven pulley system to rotate a pulley fixed to the surgical loading unit, thereby articulating the surgical loading unit relative to the adapter assembly. The adapter assembly may further include a rotation gear disposed about the articulation nut and configured to rotate the surgical loading unit. The surgical loading unit may include a lead screw for driving a translation of a knife through the surgical loading unit. The lead screw may be operably coupled to a drive shaft of the adapter assembly via a universal joint. Additional advantages of the presently disclosed surgical instruments and components thereof are described below.

FIGS. 1A and 1B illustrate a surgical instrument 10 including a handle assembly 12, an adapter assembly 20 configured to be coupled to the handle assembly 12, and a surgical loading unit 30 pivotably coupled to the adapter assembly 20. While the depicted surgical instrument 10 may be configured to fire staples, it is contemplated that the surgical instrument 10 may be adapted to fire any other suitable fastener such as clips and two-part fasteners. Additionally, while the figures depict a linear surgical stapling instrument 10, it is envisioned that certain components described herein may be adapted for use in other types of endoscopic surgical instruments including non-linear surgical stapler loading units, endoscopic forceps, graspers, dissectors, other types of surgical stapling instruments, powered vessel sealing and/or cutting devices, etc.

Generally, the adapter assembly 20 of the surgical instrument 10 includes an outer housing 21 and an outer tube 24 extending distally from the outer housing 21. The outer housing 21 includes a knob housing 22 and a coupling mechanism or proximal housing 25 extending proximally from the knob housing 22 and configured to be operably coupled to the handle assembly 12 or a surgical robotic system (not shown) responsible for actuating the surgical instrument 10. The outer tube 24 has a proximal end portion fixed within the distal end portion of the knob housing 22. In other embodiments, the outer tube 24 may be rotatable relative to and within the knob housing 22. The surgical loading unit 30 is adapted to be attached to a distal end portion 24 b of the outer tube 24 of the adapter assembly 20 and may be configured for a single use, or may be configured to be used more than once.

The surgical loading unit 30 includes a collar 32 pivotably coupled to the distal end portion 24 b of the outer tube 24 and an end effector 34 supported on the collar 32. The end effector 34 includes an anvil plate 36 non-rotationally coupled to the collar 32, and a staple cartridge assembly 37 disposed in opposed relation with the anvil plate 36. The staple cartridge assembly 37 has a chassis 38 pivotably coupled to the collar 32 and a staple cartridge body 40 configured for removable receipt in a channel 42 of the chassis 38. As shown in FIG. 4, the anvil 26 may have an elongated strain gauge 39 disposed on an underside thereof and which is electrically connectable to the handle assembly 12 to obtain direct and accurate measurement of tissue strain.

For a detailed description of the handle assembly 12, reference may be made to U.S. Patent Application Publication No. 2015/0157320, filed on Nov. 21, 2014, and U.S. Patent Application Publication No. 2016/0310134, filed on Apr. 12, 2016, the entire contents of each of which being incorporated by reference herein.

With reference to FIGS. 2-6, an articulation mechanism of the adapter assembly 20 will now be described, and is generally designated articulation mechanism 81. The adapter assembly 20 includes an articulation input shaft 50, a firing input shaft 52, and a rotation input shaft 54 each rotationally supported in the coupling mechanism 25 of the outer housing 21 (FIG. 1A). The articulation input shaft 50 has a proximal end portion 50 a configured to be drivingly coupled to a corresponding drive member 13 a of the handle assembly 12 to effect a rotation of the articulation input shaft 50. The articulation input shaft 50 has a distal end portion 50 b having a gear 56 (e.g., a spur gear) fixed thereabout.

The adapter assembly 20 includes an articulation nut 58 operably coupled to the articulation input shaft 50 and operably coupled to an articulation link 60. The articulation nut 58 may have a ring gear 62 at its proximal end and a tubular shaft 64 extending distally from the ring gear 62. The ring gear 62 of the articulation nut 58 has gear teeth interfacing with the gear 56 of the articulation input shaft 50. The tubular shaft 64 of the articulation nut 58 has a threaded inner surface 66 coupled to a proximal end portion 60 a of the articulation link 60.

The proximal end portion 60 a of the articulation link 60 is received in a channel 68 defined by the tubular shaft 64 of the articulation nut 58. The proximal end portion 60 a of the articulation link 60 has an arcuate, threaded outer surface 70 threadedly engaged with the threaded inner surface 66 of the tubular shaft 64 of the articulation link 60. As such, the articulation link 60 translates along a longitudinal axis “X” in response to a rotation of the articulation nut 58. The articulation link 60 may have a generally elongated, rectangular configuration. However, other shapes of articulation link 60 are contemplated, such as tubular. The articulation link 60 defines a longitudinally-extending passageway 72 having the firing shaft 52 slidably supported therein.

With reference to FIGS. 4-6, the articulation link 60 has a distal end portion 60 b having a fin 74 extending upwardly therefrom. The fin 74 may be a flat, elongated structure. Other shapes of the fin 74 are contemplated herein. The fin 74 has an outwardly-facing surface 76 having teeth 78 (FIG. 6) extending laterally outward therefrom. The fin 74 of the articulation link 60 is received in a central cavity 84 defined by a drive belt 82 of the articulation mechanism 81, and the teeth 78 of the fin 74 interface with teeth 80 disposed on a linear section 82 c of the drive belt 82. As such, proximal or distal translation of the articulation link 60 drives a movement of the drive belt 82 along a pathway, such as, for example, an oval-shaped pathway, in either a clockwise or counter-clockwise direction.

The articulation mechanism 81 further includes a proximal pulley 86 rotationally supported in the distal end portion 24 b of the outer tube 24 of the adapter assembly 20. The proximal pulley 86 has a curved, proximal end portion 82 a of the drive belt 82 wrapped thereabout. The collar 32 of the surgical loading unit 30 may act as a distal pulley and is rotationally fixed in the proximal end portion of the surgical loading unit 30. The collar or distal pulley 32 has a curved, distal end portion 82 b of the drive belt 82 wrapped thereabout. The proximal and distal pulleys 86, 32 may each have gear teeth interfacing with the gear teeth 80 of the drive belt 82, such that movement of the drive belt 82 rotates the pulleys 86, 32. It is contemplated that the proximal pulley 86 acts as an idler gear for maintaining tension in the drive belt 82.

The distal pulley 32 may include an upper component 32 a received in the anvil 36 of the surgical loading unit 30 and a lower component 32 b received in the chassis 38 of the staple cartridge assembly 37 of the surgical loading unit 30. Each of the upper and lower components 32 a, 32 b of the distal pulley 32 has a main body 88 a, 90 a and a gear 88 b, 90 b, such as, for example, a pinion gear extending proximally from the respective main body 88 a, 90 a. The main body 88 a of the upper component 32 a is fixed to the anvil 36 of the surgical loading unit 30, and the main body 90 a of the lower component 32 b is fixed to the chassis 38 of the staple cartridge assembly 37 of the surgical loading unit 30. The gears 88 b, 90 b of the upper and lower components 32 a, 32 b are each received in the curved, distal end portion 82 b of the drive belt 82. The upper and lower components 32 a, 32 b of the distal pulley 32 cooperatively define a channel 92 (FIG. 5) through which the curved, distal end portion 82 b of the drive belt 82 extends.

The articulation mechanism 81 further includes a proximal housing 100 and a distal housing 102 each disposed in the distal end portion 24 b of the outer tube 24 of the adapter assembly 20. The proximal housing 100 rotationally supports therein the proximal pulley 86. The proximal housing 100 is slidable within the outer tube 24, whereas the distal housing 102 is axially restrained within the outer tube 24. The distal housing 102 defines an aperture 104 having the gears 88 b, 90 b of the distal pulley 32 rotationally supported therein. A pivot pin 106 extends through the distal housing 102 and each of the gears 88 b, 90 b of the distal pulley 32 to pivotably couple the distal pulley 32, and therefore the surgical loading unit 30 as a whole, to the adapter assembly 20.

The proximal and distal housings 100, 102 are axially spaced from one another via a tension screw 108. The tension screw 108 has a proximal end portion 108 a rotationally supported and axially restrained in the proximal housing 100, and a distal end portion 108 b disposed within an elongate channel 110 defined through the distal housing 102. The distal end portion 108 b of the tension screw 108 is threadedly engaged to the distal housing 102. In this way, a rotation of the tension screw 108 adjusts the axial spacing of the proximal housing 100 from the distal housing 102 by sliding the proximal housing 100 within the outer tube 24 and relative to the distal housing 102 in either a proximal or distal direction. Adjusting the axial spacing between the proximal and distal housings 100, 102 adjusts the axial spacing between the proximal and distal pulleys 86, 32, thereby adjusting the tension in the drive belt 82.

With reference to FIG. 7A, an alternate embodiment of a drive belt 182 is illustrated and which may be used in place of the drive belt 82. The drive belt 182 is a band of single or multiple laminations wrapped about the pulleys 86, 32 and instead of having gear teeth, the drive belt 182 has a plurality of pins 186 extending radially inward from a distal end portion 182 b of the drive belt 182. The plurality of pins 186 are each received in a corresponding valley defined between adjacent gear teeth of the gear 88 b or gears 88 b, 90 b of the distal pulley 32, such that the distal pulley 32 rotates in response to movement of the drive belt 182. A proximal end portion 182 a of the drive belt 182 may be frictionally engaged to the proximal pulley 86. The drive belt 182 has a plurality of teeth 184 that extend radially inward from an intermediate portion 182 c thereof for fixedly coupling the drive belt 182 to the distal end portion 60 b (FIG. 4) of the articulation link 60.

With reference to FIG. 7B, another alternate embodiment of a drive belt 282 is illustrated and which may be used in place of the drive belt 82. The drive belt 282 is a single or a plurality of cables or wires, which are wrapped about the proximal and distal pulleys 86, 32. Instead of having gear teeth, an intermediate portion 282 c of the drive belt 282 has a first peg 284 a that fixedly couples the drive belt 282 to the distal end portion 60 b (FIG. 4) of the articulation link 60, and a distal end portion 282 b of the drive belt 282 has a second peg 284 b that fixedly couples the drive belt 282 to a circumferential edge of the gear 88 b or gears 88 b, 90 b of the distal pulley 32 (FIG. 4). Other fastening engagements are also contemplated, such as, for example, frictional engagement, adhesives, or the like. A proximal end portion 282 a of the drive belt 282 may be frictionally engaged to the proximal pulley 86 (FIG. 4).

In operation, with reference to FIGS. 3-6, to articulate the surgical loading unit 30 relative to the adapter assembly 20, the articulation input shaft 50 is rotated via an actuation of the handle assembly 12. The articulation input shaft 50 transfers rotational motion from the gear 56 fixed thereabout to the ring gear 62 of the articulation nut 58. Since the articulation nut 58 is threadedly coupled to the proximal end portion 60 a of the articulation link 60, clockwise rotation of the articulation nut 58 drives a proximal translation of the articulation link 60 in the direction indicated by arrow “A” in FIG. 6. The proximal translation of the fin 74 of the distal end portion 60 b of the articulation link 60 b moves the drive belt 82 of the articulation mechanism in a clockwise direction, indicated by arrow “B” in FIG. 6, along the oval pathway defined by the shape of the drive belt 82.

The movement of the drive belt 82 rotates the distal pulley 32 about the pivot pin 106 due to the engagement between the distal end portion 82 b of the drive belt 82 and the gears 88 b, 90 b of the distal pulley 32. Given that the distal pulley 32 is fixed to both the anvil 36 and surgical cartridge assembly 37 of the surgical loading unit 30, the rotation of the distally pulley 32 about the pivot pin 106 causes the surgical loading unit 30 as a whole to articulate relative to the adapter assembly 20 in the direction indicated by arrow “B” in FIG. 6. Similarly, as can be appreciated, distal movement of the articulation link 60 in the direction indicated by arrow “C” in FIG. 6 ultimately results in an articulation of the surgical loading unit 30 in the direction indicated by arrow “D” in FIG. 6.

With reference to FIGS. 2-5, the firing and clamping mechanism of the adapter assembly 20 will now be described. The firing input shaft 52 of the adapter assembly 20 is configured to effect a clamping and stapling function of the surgical loading unit 30. The firing input shaft 52 has a proximal end portion 52 a extending through the articulation nut 58 and the passageway 72 of the articulation link 60 and is configured to be drivingly coupled to the drive member 13 b (FIG. 1A) of the handle assembly 12. The firing input shaft 52 has a distal end portion 52 b pivotably and non-rotationally coupled to a proximal end portion 112 a of a lead screw 112 of the surgical loading unit 30.

The lead screw 112 of the surgical loading unit 30 is rotationally supported in the chassis 38 of the staple cartridge assembly 37. The proximal end portion 112 a of the lead screw 112 is operably coupled to the distal end portion 52 b of the firing input shaft 52 via a universal joint 114. In embodiments, the lead screw 112 and the firing input shaft 52 may be coupled via any suitable joint that allows for the transfer of rotational motion from the firing input shaft 52 to the lead screw 112.

As best shown in FIG. 4, the surgical loading unit 30 further includes an I-beam 116 configured to both sever tissue and pivot the staple cartridge assembly 37 toward the anvil plate 36 during distal advancement of the I-beam 116. The I-beam 116 has a sharp distally-oriented surface 118 (forming a knife) configured to sever tissue, an upper foot 120 disposed within a ramped channel 121 defined by the anvil plate 36, and a lower foot 122 threadedly engaged with the lead screw 112.

In operation, to fire and clamp the surgical loading unit 30, the firing input shaft 52 is rotated via an actuation of the handle assembly 12 attached to the coupling mechanism 25 of the adapter assembly 20. The firing input shaft 52 transfers its rotational motion to the lead screw 112 of the surgical loading unit 30 via the universal joint 114. Rotation of the lead screw 112 advances the I-beam 116 distally through the anvil plate 36 and the chassis 38, thereby pivoting the chassis 38 toward the anvil plate 36 due to the upper foot 120 of the I-beam 116 traversing the ramped channel 121 of the anvil 36. As the I-beam 116 advances distally through the anvil plate 36 and the chassis 38, any tissue disposed therebetween is severed by the sharp, distally-oriented surface 118 thereof.

With reference to FIGS. 2 and 3, the rotation mechanism of the adapter assembly 20 will now be described. The rotation input shaft 54 of the adapter assembly 20 has a proximal end portion 54 a configured to be drivingly coupled to a drive member 13 c (FIG. 1A) of the handle assembly 12 to drive a rotation of the rotation input shaft 54. The rotation input shaft 54 has a gear 126 fixed about a distal end portion 54 b thereof. The gear 126 of the rotation input shaft 54 is operably coupled to teeth 128 of a rotation gear 130 of the rotation mechanism.

The rotation gear 130 is disposed about the tubular shaft 64 of the articulation nut 58 and within the knob housing 22. A thrust plate 132 and a pair of wave springs 134 a, 134 b may be positioned between the rotation gear 130 and the articulation nut 58. The rotation gear 130 is fixed to the outer tube 24 via a fastener 136 and keyed to the articulation link 60, such that the outer tube 24 and the articulation link 60 are rotatable with the rotation gear 130. In embodiments, any suitable means for fastening the rotation gear 130 to the outer tube 24 may be provided, such as, for example, threaded engagement, frictional engagement, lock and key engagement, latches, buttons, bayonet-type connections, welding, adhesives and/or other mechanisms.

In operation, to rotate the surgical loading unit 30, the rotation input shaft 54 is rotated via an actuation of the handle assembly 12 attached to the coupling mechanism 25 of the adapter assembly 20. Rotational motion of the rotation input shaft 54 is transferred to the rotation gear 130. Since the rotation gear 130 is locked to the outer tube 24 and the articulation link 60, rotation of the rotation gear 130 results in a rotation of the outer tube 24 relative to the coupling mechanism 25, which, in turn, causes the surgical loading unit 30 to rotate about the longitudinal axis of the adapter assembly 20.

With reference to FIGS. 8-11, another embodiment of an articulation mechanism for use in the surgical instrument 10 above is illustrated. Due to the similarities between the articulation mechanism of the present embodiment and the articulation mechanism described above, only those elements of the articulation mechanism of the present embodiment deemed necessary to elucidate the differences from the articulation mechanism above will be described in detail.

The articulation mechanism includes an articulation rod 140 having a proximal end portion (not explicitly shown) configured to be operably coupled to a corresponding drive member 13 a (FIG. 1A) of the handle assembly 12. The proximal end portion of the articulation rod 140 is configured to translate along a central longitudinal axis “X” of the outer tube 24 of the adapter assembly 20 in response to an activation of the drive member 13 a of the handle assembly 12.

The articulation rod 140 has a distal end portion 140 b having a linear, first section 142 a, a linear second section 142 b extending at an obtuse angle from the first section 142 a, and a third section 142 c extending distally from the second section 142 b, whereby the first and third sections 142 a, 142 c are parallel with one another. In embodiments, the first, second, and third sections 142 a-c may be disposed at any suitable angle relative to one another. The first section 142 a of the distal end portion 140 b of the articulation rod 140 has a collar or E-clip 144 disposed thereabout. A biasing member 146, such as, for example, a coil spring, is disposed between the collar 144 of the articulation rod 140 and a proximal pivot housing 148 of the adapter assembly 20 for resiliently biasing the articulation rod 140 in a proximal direction to prevent joint backlash.

The proximal pivot housing 148 of the adapter assembly 20 has a proximal end portion 148 a disposed in the distal end portion 24 b of the outer tube 24 and a distal end portion 148 b extending distally from the distal end portion 24 b of the outer tube 24. The third section 142 c of the distal end portion 140 b of the articulation rod 140 extends through a longitudinally-extending channel 150 defined through the proximal pivot housing 148 and is laterally offset from the central longitudinal axis “X” defined by the outer tube 24. The distal end portion 148 b of the proximal pivot housing 148 is pivotably coupled to a distal pivot housing 152 fixed to the proximal end portion of the surgical loading unit 30.

The distal pivot housing 152 of the surgical loading unit 30 has a main body 154 fixed within the anvil 36 and chassis 38, and a platform 156 extending proximally from the main body 154. The main body 154 and the platform 156 cooperatively define a slot 158 for receipt of an articulation link 160. The articulation link 160 has a proximal end portion 160 a pivotably coupled to the third section 142 c of the distal end portion 140 b of the articulation rod 140, and a distal end portion 160 b that extends through the slot 158 of the distal pivot housing 152 and pivotably couples to the main body 154 of the distal pivot housing 152. The articulation link 160 may define a recess 162 in a lateral side thereof for the passage of a pivot pin 164 that pivotably couples the proximal and distal housings 148, 152 to one another.

In operation, to articulate the surgical loading unit 30 relative to the adapter assembly 20, the articulation rod 140 is translated via an actuation of the handle assembly 12 (FIG. 1A). Since the third section 142 c of the distal end portion 140 b of the articulation rod 140 is pivotably coupled to the proximal end portion 160 a of the articulation link 160, and the distal end portion 160 b of the articulation link 160 is pivotably coupled to the distal pivot housing 152 of the surgical loading unit 30, distal advancement of the articulation rod 140 causes the articulation link 160 to rotate about the pivot pin 164, whereby the surgical loading unit 30 articulates about the pivot pin 164 and relative to the adapter assembly 20. Similarly, as can be appreciated, proximal retraction of the articulation rod 140 drives an articulation of the surgical loading unit 30 in the opposite direction.

It is contemplated that the articulation mechanisms, stapling and clamping mechanisms, and rotation mechanisms described herein may be incorporated into surgical instruments other than surgical instrument 10.

Persons skilled in the art will understand that the adapter assemblies and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. An adapter assembly, comprising: an articulation nut; an articulation link having a proximal end portion operably coupled to the articulation nut, such that rotation of the articulation nut results in translation of the articulation link; a drive belt operably coupled to a distal end portion of the articulation link, wherein the drive belt has a distal end portion configured to be operably coupled to a proximal end portion of a surgical loading unit, such that movement of the drive belt articulates the surgical loading unit relative to the adapter assembly; an outer housing having the articulation nut rotationally supported therein; an outer tube extending distally from the outer housing, the outer tube having the articulation link axially supported therein; and a rotation gear disposed about the articulation nut and within the outer housing, wherein the rotation gear is non-rotationally fixed to the outer tube, such that the outer tube is configured to rotate about a longitudinal axis thereof in response to a rotation of the rotation gear.
 2. The adapter assembly according to claim 1, further comprising a pulley operably coupled to a proximal end portion of the drive belt, the drive belt being wrapped about the pulley.
 3. The adapter assembly according to claim 2, further comprising: a proximal housing having the pulley rotationally supported therein; a distal housing having a distal end portion configured to be pivotably coupled to the proximal end portion of the surgical loading unit; and a tension screw disposed between the proximal and distal housings and configured to adjust a distance from which the proximal housing is spaced from the distal housing and, in turn, adjust a tension in the belt drive.
 4. The adapter assembly according to claim 1, wherein the distal end portion of the articulation link is operably coupled to a linear section of the drive belt.
 5. The adapter assembly according to claim 1, wherein the distal end portion of the articulation link has teeth, and the drive belt has teeth on an inner surface thereof interfacing with the teeth of the articulation link.
 6. The adapter assembly according to claim 5, wherein the articulation link includes a fin extending from the distal end portion thereof, the teeth of the articulation link being disposed on an outwardly-facing surface of the fin.
 7. The adapter assembly according to claim 6, wherein the fin of the articulation link is enclosed by the drive belt.
 8. The adapter assembly according to claim 1, wherein the proximal end portion of the articulation link is received in the articulation nut.
 9. The adapter assembly according to claim 8, wherein the proximal end portion of the articulation link has a threaded outer surface interfacing with a threaded inner surface of the articulation nut.
 10. The adapter assembly according to claim 1, further comprising an articulation input shaft, wherein the articulation nut has teeth on an outer surface thereof interfacing with teeth on the articulation input shaft.
 11. A surgical instrument, comprising: an adapter assembly including: an articulation nut; an articulation link having a proximal end portion operably coupled to the articulation nut, such that rotation of the articulation nut results in translation of the articulation link; a drive belt operably coupled to a distal end portion of the articulation link; a second pulley operably coupled to a proximal end portion of the drive belt; and a proximal housing having the second pulley rotationally supported therein; and a surgical loading unit having a first pulley non-rotationally fixed in a proximal end portion thereof, wherein the drive belt has a distal end portion operably coupled to the first pulley, such that movement of the drive belt rotates the first pulley to articulate the surgical loading unit relative to the adapter assembly, the drive belt being wrapped about the first and second pulleys, the adapter assembly further including: a distal housing having the first pulley rotationally supported therein; and a tension screw disposed between the proximal and distal housings and configured to adjust a distance from which the proximal housing is spaced from the distal housing and, in turn, adjust a tension in the belt drive.
 12. The surgical instrument according to claim 11, wherein the distal end portion of the articulation link has teeth, and the drive belt has teeth on an inner surface thereof interfacing with the teeth of the articulation link.
 13. The surgical instrument according to claim 12, wherein the articulation link includes a fin extending from the distal end portion thereof, the teeth of the articulation link being disposed on an outwardly-facing surface of the fin.
 14. The surgical instrument according to claim 11, wherein the proximal end portion of the articulation link is received in the articulation nut and has a threaded outer surface interfacing with a threaded inner surface of the articulation nut.
 15. The surgical instrument according to claim 11, wherein the surgical loading unit includes: an anvil; a staple cartridge assembly pivotably coupled to the anvil; a lead screw disposed within the staple cartridge assembly; and a knife operably coupled to the lead screw, the knife being configured to move through the staple cartridge assembly to pivot the staple cartridge assembly toward the anvil in response to a rotation of the lead screw.
 16. The surgical instrument according to claim 15, wherein the adapter assembly further includes a rotatable drive shaft having a distal end portion coupled to a proximal end portion of the lead screw via a universal joint.
 17. An adapter assembly, comprising: an articulation nut; an articulation link having a proximal end portion operably coupled to the articulation nut, such that rotation of the articulation nut results in translation of the articulation link; and a drive belt operably coupled to a distal end portion of the articulation link, wherein the drive belt has a distal end portion configured to be operably coupled to a proximal end portion of a surgical loading unit, such that movement of the drive belt articulates the surgical loading unit relative to the adapter assembly, wherein the distal end portion of the articulation link has teeth, and the drive belt has teeth on an inner surface thereof interfacing with the teeth of the articulation link, and wherein the articulation link includes a fin extending from the distal end portion thereof, the teeth of the articulation link being disposed on an outwardly-facing surface of the fin.
 18. The adapter assembly according to claim 17, wherein the fin of the articulation link is enclosed by the drive belt.
 19. The adapter assembly according to claim 17, wherein the proximal end portion of the articulation link is received in the articulation nut.
 20. The adapter assembly according to claim 19, wherein the proximal end portion of the articulation link has a threaded outer surface interfacing with a threaded inner surface of the articulation nut. 